Réaction #70661

Équation de réaction

tert-butyl lithium

acetone dry ice

THF

4-bromobenzocyclobutane

tert-Butyllithium

→

3-(4-bromobutyl)bicyclo[4.2.0]octa-1(6),2,4-triene

Conditions de réaction

Traitement

1. 1
   AutreTo an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen
2. 2
   Autreto the reaction
3. 3
   workup.ADDITIONthrough the addition
4. 4
   Autrethe reaction temperature below −65° C
5. 5
   Autrethe dry ice/acetone bath was removed
6. 6
   Températurecooled down to −73° C. in dry ice/acetone bath
7. 7
   workup.ADDITION65.7 mL 1,4-dibromobutane was added drop-wise via syringe
8. 8
   Autrestayed lower than −65° C
9. 9
   Températureto slowly warm to room temperature overnight
10. 10
    AutreThe reaction was quenched by the addition of isopropanol (25 mL)
11. 11
    Autrethe solvent was removed by rotary evaporation
12. 12
    workup.ADDITIONEthyl acetate (500 mL) was added
13. 13
    Extractionextracted with DI water (1000 mL×2) and brine (200 mL×5)
14. 14
    SéchageThe combined organic layer was dried over anhydrous magnesium sulfate
15. 15
    Autrethe solvent was removed by evaporation
16. 16
    Autrewas removed by vacuum
17. 17
    workup.DISTILLATIONdistilled at 90° C
18. 18
    FiltrationFiltration through a Celite/silica gel plug
19. 19
    Autreafforded 24.1 g NMR and GC-MS pure product

Mode opératoire

To an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen, were added 500 mL anhydrous THF and 25.0 g 4-bromobenzocyclobutane. The reaction mixture was then cooled down to −73° C. in acetone/dry ice bath. 161 mL tert-Butyllithium (2M) was added drop by drop to the reaction through the addition, while keeping the reaction temperature below −65° C. After addition of tert-butyl lithium, the dry ice/acetone bath was removed and the reaction was allowed to warm up to −20° C., and then cooled down to −73° C. in dry ice/acetone bath. 65.7 mL 1,4-dibromobutane was added drop-wise via syringe, ensuring the reaction temperature stayed lower than −65° C. The reaction was allowed to slowly warm to room temperature overnight. The reaction was quenched by the addition of isopropanol (25 mL), and the solvent was removed by rotary evaporation. Ethyl acetate (500 mL) was added and then extracted with DI water (1000 mL×2) and brine (200 mL×5). The combined organic layer was dried over anhydrous magnesium sulfate, and the solvent was removed by evaporation. The excess starting material, 1,4-dibromobutane, was removed by vacuum distilled at 90° C. Filtration through a Celite/silica gel plug afforded 24.1 g NMR and GC-MS pure product.

Source